How to add an event to a class

Question

Say I have a class named Frog, it looks like:

public class Frog
{
     public int Location { get; set; }
     public int JumpCount { get; set; }


     public void OnJump()
     {
         JumpCount++;
     }

}

I need help with 2 things:

1. I want to create an event named Jump in the class definition.
2. I want to create an instance of the Frog class, and then create another method that will be called when the Frog jumps.

Answer 1

public event EventHandler Jump;
public void OnJump()
{
    EventHandler handler = Jump;
    if (null != handler) handler(this, EventArgs.Empty);
}

then

Frog frog = new Frog();
frog.Jump += new EventHandler(yourMethod);

private void yourMethod(object s, EventArgs e)
{
     Console.WriteLine("Frog has Jumped!");
}

Answer 2

I'm not too clear on your question. Do you want to know the syntax for events? Why not look at the tutorial in the official documentation?

Answer 3

@CQ: Why do you create a local copy pf Jump? Additionally, you can save the subsequent test by slightly changing the declaration of the event:

public event EventHandler Jump = delegate { };

public void OnJump()
{
    Jump(this, EventArgs.Empty);
}